Input apparatus

ABSTRACT

An input apparatus has an input unit for receiving a pressure input, a load detection unit for detecting a pressure load on the input unit, a vibration unit for vibrating the input unit, and a control unit for controlling drive of the vibration unit 14 such that a click sensation is provided to an object pressing the input unit when the pressure load detected by the load detection unit satisfies a predetermined standard for receiving an input to the input unit. Thereby, a realistic click sensation similar to that obtained when a push-button switch is operated is provided upon operation of the input unit of a pressure type by an operator.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Japanese PatentApplications No. 2008-326281, No. 2008-326316 and No. 2008-326311 filedon Dec. 22, 2008, the entire contents of which are incorporated hereinby reference.

TECHNICAL FIELD

The present invention relates to input apparatuses having input unitsfor receiving pressure inputs.

BACKGROUND ART

In recent years, input apparatuses having input units in the form of aplate for receiving inputs by pressure such as touch panels, touchswitches and the like are popularly used as input units for receivinginput operations by the user in information equipments, home electricappliances and the like. Such input units have a variety of types, suchas resistive film type, capacitive type and the like. All of these inputunits are for receiving pressure inputs by fingers and stylus pens and,unlike push-button switches, they are not displaced even when beingpressed.

Therefore, an operator cannot obtain feedback when the pressure input isreceived by the input unit. As a result, when using the input apparatushaving the touch panel, for example, the operator is likely to inputerroneously by tapping multiple times on the same spot, which may bestressful for the operator.

As methods to prevent such erroneous inputs, there are known methods forvisually or auditory confirming the input operations by, for example,generating sounds or by changing a display state, such as colors ofinput objects such as input buttons and the like graphically displayedon a display unit, correspondingly to a pressured area upon reception ofthe pressure inputs.

However, such auditory feedback may be difficult to be confirmed in anoisy environment and is not applicable when the equipment being used isin a silent mode. In addition, in using such visual feedback, if theinput object displayed on the display unit is small, the operator maynot be able to confirm the change in the display state, and particularlywhen the operator is inputting by a finger, a view of the input objectis blocked by the finger.

There is also suggested a feedback method relying on neither theauditory nor visual sensation but instead generating a tactile sensationat operator's fingertip by vibrating the touch panel upon reception ofan input thereon (for example, see Patent Documents 1, 2).

RELATED ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Patent Laid-Open No. 2003-288158-   Patent Document 2: Japanese Patent Laid-Open No. 2008-130055

SUMMARY OF INVENTION Technical Problem

The techniques disclosed in the above Patent Documents 1 and 2, however,merely generate the tactile sensation at the operator's fingertip. Thatis, they provide a mere “throbbing” sensation at the operator'sfingertip touching the touch panel and not a realistic click sensationsuch as “click” which is obtained when operating, for example, apush-button switch with a metal dome.

Therefore, the operator may have a feeling of strangeness if the abovefeedback techniques are applied to the touch panels of, for example,input keys of the information equipments such as mobile terminals ofmobile phones, calculators, ticket vending machines and the like andinput keys of operation units of the home electric appliances such asmicrowaves, TV sets and the like.

Accordingly, an object of the present invention in consideration of suchconditions is to provide an input apparatus capable of providing therealistic click sensation, similar to that obtained when the push-buttonswitch is operated, when an operator operates the input unit of apressure type.

Solution to Problem

In order to achieve the above object, an input apparatus according to afirst aspect of the present invention includes:

an input unit for receiving a pressure input;

a load detection unit for detecting a pressure load on the input unit;

a vibration unit for vibrating the input unit; and

a control unit for controlling drive of the vibration unit such that aclick sensation is provided to an object pressing the input unit whenthe pressure load detected by the load detection unit satisfies apredetermined standard for receiving an input to the input unit.

In addition, in order to achieve the above object, an input apparatusaccording to a second aspect of the present invention includes:

an input unit for receiving a pressure input;

a load detection unit for detecting a pressure load on the input unit;

a vibration unit for vibrating the input unit; and

a control unit for controlling drive of the vibration unit to vibratethe input unit at a frequency such that a click sensation is provided toan object pressing the input unit when the pressure load detected by theload detection unit satisfies a predetermined standard for receiving aninput to the input unit.

Moreover, in order to achieve the above object, an input apparatusaccording to a third aspect of the present invention includes:

an input unit for receiving a pressure input;

a load detection unit for detecting a pressure load on the input unit;

a vibration unit for vibrating the input unit; and

a control unit for controlling drive of the vibration unit such that aclick sensation is provided to an object pressing the input unit whenthe pressure load detected by the load detection unit satisfies apredetermined standard for receiving an input to the input unit, and forcontrolling drive of the vibration unit such that the click sensation isprovided to the object when the pressure load detected by the loaddetection unit satisfies a predetermined standard after the input to theinput unit is received.

Effect of the Invention

According to the first aspect of the present invention, the input unitvibrates if the pressure load on the input unit satisfies apredetermined standard for receiving an input. Thereby, it is possibleto provide the operator with a realistic click sensation similar to thatobtained when a push-button switch is operated.

According to the second aspect of the present invention, the input unitvibrates at a frequency if the pressure load on the input unit satisfiesa predetermined standard for receiving an input. Thereby, it is possibleto provide the operator with the realistic click sensation similar tothat obtained when the push-button switch is operated.

According to the third aspect of the present invention, the input unitvibrates if the pressure load on the input unit satisfies apredetermined standard for receiving an input and then the input unitvibrates if the pressure load on the input unit satisfies apredetermined standard. Thereby, it is possible to provide the operatorwith the realistic click sensation similar to that obtained when thepush-button switch is operated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a general load characteristic of apush-button switch;

FIG. 2 is a diagram illustrating results of sensory evaluations onoperations of a variety of push-button switches with different pressureloads;

FIG. 3 is a diagram illustrating results of sensory evaluations onoperations of a variety of push-button switches with different strokes;

FIG. 4 is a diagram illustrating an exemplary result of a measurement ofa vibration generated at a push button upon operation of the push-buttonswitch;

FIG. 5 is a block diagram illustrating a schematic constitution of aninput apparatus according to a first embodiment of the presentinvention;

FIG. 6 shows an exemplary housing structure of the input apparatus shownin FIG. 5;

FIG. 7 is a flowchart of operations by the input apparatus shown in FIG.5;

FIG. 8 is a block diagram illustrating a schematic constitution of aninput apparatus according to a second embodiment of the presentinvention;

FIG. 9 is a front view of the input apparatus shown in FIG. 8;

FIG. 10 is a diagram illustrating results of sensory evaluations on aclick sensation when varying frequency of a drive signal to drive thevibration unit shown in FIG. 5;

FIG. 11 is a diagram illustrating results of sensory evaluations on theclick sensation when varying vibration amplitude of a touch panel shownin FIG. 5;

FIG. 12 is a diagram illustrating results of sensory evaluations on theclick sensation when varying period of the drive signal to drive thevibration unit shown in FIG. 5;

FIG. 13 is a diagram illustrating results of sensory evaluations on theclick sensation when varying waveform of the drive signal to drive thevibration unit shown in FIG. 5;

FIG. 14 is a diagram illustrating the waveform of the drive signal todrive the vibration unit and an actual waveform of the vibrationamplitude on the touch panel;

FIG. 15 is a flowchart of operations by an input apparatus according toa third embodiment of the present invention;

FIG. 16 is a diagram illustrating an example of click sensation providedby the input apparatus according to the third embodiment when a standardload of pressing and that of releasing are set to be equal;

FIG. 17 is a diagram illustrating an example of click sensation providedby the input apparatus according to the third embodiment when thestandard load of releasing is set to be less than that of pressing;

FIG. 18 is a diagram illustrating an exemplary result of sensoryevaluations on the click sensation by the input apparatus according tothe third embodiment comparing with and without a release tactilesensation;

FIG. 19 is a diagram illustrating an example of sensation provided uponcontinuous input when the standard load of pressing and that ofreleasing are set to be equal;

FIG. 20 is a diagram illustrating an example of sensation provided uponcontinuous input when the standard load of releasing is set to be toolow relative to that of pressing;

FIG. 21 is a diagram illustrating an example of sensation provided uponcontinuous input when the standard load of releasing is set close tothat of pressing;

FIG. 22 is a diagram illustrating exemplary results of sensoryevaluations on sensation provided by an input apparatus according to afourth embodiment of the present invention when the standard load ofpressing is set at 1 N;

FIG. 23 is a diagram illustrating exemplary results of sensoryevaluations on sensation provided by the input apparatus according tothe fourth embodiment of the present invention when the standard load ofpressing is set at 2 N; and

FIG. 24 is a diagram illustrating exemplary results of sensoryevaluations on sensation provided by the input apparatus according tothe fourth embodiment of the present invention when the standard load ofpressing is set at 3 N.

DESCRIPTION OF EMBODIMENTS

Prior to descriptions of embodiments of the present invention, adescription of a principle of a method to provide a click sensation byan input apparatus according to the present invention is presented.

For tactile sensory awareness, a human has a nerve responsible for apressure sensation to feel a tactile sensation such as hardness orsoftness of an object from a load introduced to a bone and a muscle whentouching the object, and another nerve responsible for a tactilesensation to feel a texture of the object and the like by detecting avibration introduced to a skin surface when touching the object. Thatis, the pressure sensation detects the load, whereas the tactilesensation detects the vibration. In addition, a tactile sensation isgenerally a combination of the pressure sensation and the tactilesensation. Accordingly, reproduction of a stimulus, similar to thestimulus to the “pressure sensation” and the “tactile sensation” whenoperating a push-button switch, on a touch panel enables to provide aclick sensation to an operator.

On the other hand, metal dome switches, emboss switches, rubberswitches, tactile switches and the like, for example, are widely knownas the push-button switches used for information equipments and homeelectric appliances. Although there are differences in the stroke of apush-button and the applied load (pressing force) according to types ofthe switches, those general push-button switches basically have loadcharacteristics as shown in FIG. 1.

In the load characteristics in pressing in FIG. 1, a period from a pointA to a point B represents a period in which a load increases insubstantially proportion to pressing down from a start of pressing thepush button. A period from the point B to a point C represents a periodin which a convex elastic member such as the metal dome is buckled sincethe push button is pressed down, and thus the load is rapidly decreased.A period from the point C to a point D represents a period in which acontact point of the switch is closed and the load increases insubstantially proportion to pressing down.

Although there is a hysteresis to some degrees, the load characteristicsof the push button in releasing retrace a change of the load inpressing. That is, a period from the point D to a point E represents aperiod in which the load decreases in substantially promotion to releasefrom a start thereof and the contact point of the switch maintains aclosed state. A period from the point E to a point F represents a periodin which the elastic member recovers in a convex form from a buckledform by release of the push button and the load increases rapidly, andat start of this period the contact point of the switch is open. Aperiod from the point F to a point G represents a period in which afinger is released from the push button after recovery of the elasticmember and the load decreases in substantially proportion to therelease.

In the load characteristics shown in FIG. 1, a maximum stroke of thepush button is minimal; equal to or less than 1 mm for the metal domeswitch, the emboss switch and the tactile switch and equal to or lessthan 3 mm for the rubber switch, for example. In addition, loads at thepoint B are around 1 N to 6 N, for example, on the metal dome switch,the emboss switch and the tactile switch and around 0.5 N, for example,on the rubber switch. The operator can feel the click sensation whenoperating any of those push-button switches.

As such, inventors of the present invention studied what kind ofmovement of the push-button switch provides the click sensation createdby the “pressure sensation” and the “tactile sensation”. First, it isstudied which causes the click sensation, change in the stroke or changein the pressure load.

FIG. 2 is a diagram illustrating results of sensory evaluations on howthe operator felt when operating a variety of push-button switches withdifferent pressure loads. A horizontal axis represents an actualpressure load and a vertical axis represents how operators felt aboutthe push-button switches, heavy or light, on a scale of 1 to 7. Subjectsas the operators were five people who were accustomed to use of mobileterminals. As can be seen in FIG. 2, it is shown that they could perceptthat push-button switches with high pressure loads were heavy and otherswith low pressure loads were light.

FIG. 3 is a diagram illustrating results of sensory evaluations on howthe operators felt when operating a variety of push-button switches withdifferent strokes. A horizontal axis represents actual strokes and avertical axis represents how the operators felt about the push-buttonswitches, long or short, on a scale of 1 to 7. Subjects as the operatorswere five people, the same as those in FIG. 2, who were accustomed touse of mobile terminals. As can be seen in FIG. 3, they could notclearly percept whether a minimal stroke was long or short.

The results of sensory evaluations presented above shows that the humancan percept a difference in the load but not a difference in the minimalstroke.

Therefore, the inventors focused on a change in the pressure load. Thatis, since the human cannot percept the difference in the stroke, it wasstudied whether the human can feel the click sensation if the pressureload on a plane such as a touch panel, that is, a stimulus to thepressure sensation is changed following the points A, B and C in FIG. 1.Therefore, an experimental apparatus having a plate displaceable in avertical direction was prepared. Then, the plate was pressed down fromthe point A to the point B as shown in FIG. 1, and at a point when aload reached the load at the point B the plate was instantaneouslydisplaced downward slightly in order to reproduce the change in the loadbetween the points B, C.

As a result, although a “sense of pressing” to “have pressed down” thepush-button switch was obtained, the realistic click sensation such as“click” which could be obtained when operating the metal dome switch,for example, was not obtained. That is, it was found out that there isanother element, which cannot be cleared by a relationship between thestroke and the load, in order to obtain the realistic click sensation.

As such, the inventors next studied focusing not only on the “pressuresensation” but also the “tactile sensation”, which is anothersensibility. Accordingly, with a variety of mobile terminals having theinput apparatus with the push-button switches of the metal dome switchesmounted thereon, the inventors measured vibrations generated at pushbuttons when the push buttons were operated. As a result, it was foundout that at a point when the pressure load reached the point B in FIG.1, that is, at a point when the metal dome started being buckled, thepush button vibrated at a frequency of approximately 100-200 Hz.

FIG. 4 is a diagram illustrating an exemplary result of suchmeasurement. A horizontal axis represents a pressure elapsed time,whereas a vertical axis represents vibration amplitude. This push-buttonswitch vibrates as shown by a solid line in FIG. 4 at the point B inFIG. 1. Thereby, it was found out that the human receives 1 period ofvibration stimulus of about 6 ms (a frequency of approximately 170 Hz)when pressing this push-button switch. In addition, at a point when thepressure load on the push-button switch reached the point F in FIG. 1 inreleasing, that is, at a point when the metal dome recovered from thebuckled state, this push button vibrated as shown by the dashed line inFIG. 4. Thereby, it was found out that in case of this push-buttonswitch the human receives 1 period of the vibration stimulus of about 8ms (a frequency of approximately 125 Hz) at release.

The above results show that it is possible to provide the operator withthe click sensation similar to that obtained when operating thepush-button switch having the result of measurement as shown in FIG. 4,when the operator presses down the input unit of a pressure type in theform of a plate such as the touch panel, if the input apparatusstimulates the pressure sensation by letting the operator voluntarilypress down the input unit without vibration when the load is from thepoint A to the point B shown in FIG. 1 and, at the point B, stimulatesthe tactile sensation by vibrating the input unit for 1 period at thefrequency of 170 Hz.

Based on the above principle, when the input unit of the pressure typein the form of the plate is pressed down, the input apparatus accordingto the present invention stimulates the pressure sensation until thepressure load satisfies a predetermined standard for receiving an inputto the input unit and, when the standard is satisfied, stimulates thetactile sensation by vibrating the input unit with a predetermined drivesignal, that is, with a frequency, period which means drive time(wavelength), waveform and vibration amplitude. Thereby, the inputapparatus provides the operator with the realistic click sensationsimilar to that obtained upon pressing down the push-button switch.

In addition, when operating the push-button switch, the human receives atactile stimulus as shown in FIG. 4 at a finger from the push-buttonswitch not only in pressing but also in releasing. As such, the inputapparatus according to the present invention provides the operator withthe click sensation in releasing as well (hereinafter, the clicksensation in releasing is also referred to as a release tactilesensation, arbitrarily). Thereby, the input apparatus provides theoperator with a more realistic click sensation similar to that obtainedupon pressing the push-button switch down.

Embodiments of the present invention will be described with reference tothe accompanying drawings.

First Embodiment

FIG. 5 is a block diagram illustrating a schematic constitution of aninput apparatus according to a first embodiment of the presentinvention. This input apparatus has a display panel 11, a touch panel12, a load detection unit 13, a vibration unit 14, and a control unit 15for controlling overall operations. The display panel 11 constitutes adisplay unit for displaying input objects such as an input button andthe like and may be, for example, a liquid crystal display panel, anorganic EL display panel or the like. The touch panel 12 constitutes theinput unit for receiving a pressure input to the display panel 11 andmay be of a known type such as, for example, a resistive film type, acapacitive type or the like. The load detection unit 13 detects apressure load on the touch panel 12 and may include, for example, astrain gauge sensor. The vibration unit 14 vibrates the touch panel 12and may include, for example, a piezoelectric vibrator.

FIG. 6 shows an example of housing structure of the input apparatusshown in FIG. 5; FIG. 6( a) is a cross-sectional view of a main section,and FIG. 6( b) is a plane view of the main section. The display panel 11is contained in a housing 21. A touch panel 12 is disposed on thedisplay panel 11 via insulators 22 made of elastic members. In the inputapparatus according to the present embodiment, the display panel 11 andthe touch panel 12 are rectangular in shape in a planer view and thetouch panel 12 is disposed on the display panel 11 via the insulators22, which are arranged outside a display area A of the display panel 11shown by a chain double-dashed line in FIG. 6( b).

In addition, the housing 21 is provided with an upper cover 23 coveringa surface area of the touch panel 12 outside the display area of thedisplay panel 11. Insulators 24 made of elastic members are arrangedbetween the upper cover 23 and the touch panel 12.

The touch panel 12 may have a surface, that is, an operation planeconstituted by a transparent film and a rear face constituted by a glassplate and may be designed such that the transparent film of the surfaceis bent (strained) slightly in accordance with the pressure when theoperation plane is pressed.

A strain gauge sensor 31 for detecting a load (pressuring force) appliedon the touch panel 20 is provided, adhered or the like, on thetransparent film of the surface of the touch panel 12 at a positionclose to each side covered by the upper cover 23. In addition, apiezoelectric vibrator 32 for vibrating the touch panel 12 is provided,adhered or the like, on the glass plate of the rear face of the touchpanel 12 close to an edge of each of two opposed sides. That is, theinput apparatus shown in FIG. 6 has the load detection unit 13 in FIG. 5including four strain gauge sensors 31 and the vibration unit 14including two piezoelectric vibrators 32. It is to be noted that thehousing 21, the upper cover 23 and the insulator 24 shown in FIG. 6( a)are omitted in FIG. 6( b).

FIG. 7 is a flowchart of operations by the input apparatus according tothe present invention. The control unit 15 monitors an input to thetouch panel 12 as well as a load detected by the load detection unit 13.The control unit 15 detects that the input to the touch panel 12 is aninput to the input object displayed on the display panel 11, and thatthe pressure load detected by the load detection unit 13 increases withpressure on the touch panel 12 and reaches a predetermined standard forreceiving the input (step S81). Upon detecting that, the control unit 15receives the input to the touch panel 12 at a point of detection anddrives the vibration unit 14 with a predetermined drive signal tovibrate the touch panel 12 in a predetermined vibration pattern (stepS82). Thereby, the click sensation is provided to the operator via afinger or an object such as a stylus pen which is pressing the touchpanel 12, such that the operator recognizes that an input operation iscompleted. The load detection unit 13 detects the load from, forexample, an average output value of the four strain gauge sensors 31. Inaddition, the vibration unit 14 drives, for example, two piezoelectricvibrators 32 in phase.

Here, the predetermined standard used for detection at step S81 is, forexample, the load at the point B shown in FIG. 1. Accordingly, thispredetermined standard may be appropriately set in accordance with theload characteristics of an intended push-button switch in pressing. Forthe mobile terminals, for example, the predetermined standard may be setby users as desired such that elder users may set it heavier, whereasusers who often write messages may set it lighter. In addition, thepredetermined drive signal to drive the vibration unit 14 at step S82,that is, a frequency, period (wavelength), waveform and vibrationamplitude to stimulate the tactile sensation may be set appropriatelyaccording to the click sensation to be provided. For example, in orderto provide the click sensation represented by the metal dome switch usedfor the mobile terminals, at a point when the predetermined load isapplied on the touch panel 12, the vibration unit 14 is driven by adrive signal, for example a sine wave with a constant frequency of 170Hz, for 1 period so as to vibrate the touch panel 12 by approximately 15μm while a predetermined load is being applied thereon, as stated below.Thereby, it is possible to provide the operator with the realistic clicksensation.

As set forth above, the input apparatus according to the presentembodiment stimulates the pressure sensation until the load applied tothe touch panel 12 and detected by the load detection unit 13 satisfiesthe predetermined standard for receiving an input to the touch panel 12and, when the predetermined standard is satisfied, stimulates thetactile sensation by driving the vibration unit 14 with thepredetermined drive signal such that the touch panel 12 is vibrated inthe predetermined vibration pattern. Thereby, the input apparatusprovides the operator with the click sensation such that the operatorrecognizes that the input operation is completed. Accordingly, beingable to perform the input operation with feeling the realistic clicksensation similar to that obtained when operating the push-buttonswitch, the operator may not have a feeling of strangeness. Moreover,since the operator performs the input operation in conjunction with aperception to “have tapped” the touch panel 12, it prevents erroneousinputs caused by mere tapping.

Second Embodiment

FIG. 8 and FIG. 9 illustrate an input apparatus according to a secondembodiment of the present invention; FIG. 8 is a block diagram of aschematic constitution and FIG. 9 is a front view thereof. This inputapparatus is mounted on, for example, the mobile terminal and, as shownin FIG. 8, has a touch panel 41 as the input unit for receiving apressure input, a position detection unit 42 for detecting an inputposition on the touch panel 41, a display panel 43 for displayinginformation based on the input position detected by the positiondetection unit 42, a load detection unit 44 for detecting a pressureload on the touch panel 41, a vibration unit 45 for vibrating the touchpanel 41 and a control unit 46 for controlling overall operations.

As shown in FIG. 9, a plurality of input objects 41 a such as numerickeys are already provided on the touch panel 41 by printing, a stickerand the like. For each input object 41 a, in order to prevent anerroneous input to press a plurality of adjacent input objects 41 a, aneffective pressing area for receiving an input is set to be smaller thana disposition area of the input object 41 a. It is to be noted that, inFIG. 8, the load detection unit 44 and the vibration unit 45 have straingauge sensors and piezoelectric vibrators, respectively, in the samemanner as those of the input apparatus shown in FIG. 6.

The control unit 46 monitors an input to the touch panel 41 and a loaddetected by the load detection unit 44, as well as monitoring an inputposition on the touch panel 41 detected by the position detection unit42. When the position detection unit 42 detects an input position in theeffective pressing area of the input object, and when a pressure loaddetected by the load detection unit 44 increases with pressure on thetouch panel 41 and satisfies a predetermined standard for receiving aninput, the vibration unit 45 is driven with a predetermined drive signalto vibrate the touch panel 41 in a predetermined vibration pattern.

That is, if the position detection unit 42 detects the input position inthe effective pressing area of the input object, the control unit 46, inthe same manner as the input apparatus according to the firstembodiment, drives the vibration unit 45 with a drive signal, forexample a sine wave with a constant frequency of 170 Hz, for 1 period ata point when the load on the touch panel 41 increases and satisfies thepredetermined standard, in order to vibrate the touch panel 41 byapproximately 15 μm while the predetermined load is being appliedthereon. Thereby, the operator is provided with the click sensation soas to recognize that the input operation is completed. In addition, byreceiving the input detected on the touch panel 41, the control unit 46displays according to the input on the display panel 43.

Hence, according to the input apparatus according to the presentinvention, in the same manner as the first embodiment, since being ableto perform the input operation on the touch panel 41 with feeling therealistic click sensation, which is the same as that obtained whenoperating the push-button switch, the operator does not have the feelingof strangeness. Moreover, since the operator performs the inputoperation in conjunction with the perception to “have tapped” the touchpanel 41, it prevents erroneous inputs caused by mere tapping.

The following is description of the results of sensory evaluations onthe click sensation of the input apparatus according to each of theabove embodiments examined by the inventors.

According to measurements by the inventors, the metal dome switcheswidely used for commercially available mobile terminals, although thereare deviations to some degrees according to models, have the loadcharacteristics that the load is rapidly decreased when a predeterminedload, roughly equal to or less than 6 N and generally equal to or lessthan 3 N, is applied thereto. As such, the inventors conducted thesensory evaluations of the click sensation of the input apparatusdesigned as shown in FIG. 5 and FIG. 6, with a load of 1.5 N (load atthe point B in FIG. 1) on the touch panel 12 for starting drive of thevibration unit 14, and the frequency, the period (wavelength) and thewaveform of the drive signal are used as parameters.

Exemplary results of the evaluations are shown in FIG. 10 to FIG. 13. InFIG. 10 to FIG. 13, the subjects were the five people involved in thesensory evaluations shown in FIG. 2 and FIG. 3. Three evaluation itemswere “feel click sensation”, “good feeling” and tactile sensation“similar to mobile terminal”. For the item “feel click sensation”, “No”scores 1 and “Strongly feel” scores 7. For the item “good feeling”,“Bad” scores 1 and “Good” scores 7. For the item “similar to mobileterminal”, “not similar” scores 1 and “very similar” scores 7. The scoreof each item represents an average score of the five people.

FIG. 10 shows results of evaluations when varying the frequency. In thesensory evaluations, the period (wavelength) of the drive signal todrive the vibration unit 14, that is, the drive time was 1 period, thewaveform was the sine wave and the frequency was varied in a range of50-250 Hz. The amplitude of the drive signal was set to a level at whichthe vibration amplitude of 15 μm can be obtained in a state of apredetermined standard load being applied on the touch panel 12. As canbe seen in FIG. 10, it was confirmed that, although the highestevaluation was obtained at the frequency of 170 Hz, the human can obtainthe click sensation similar to that of the mobile terminals at afrequency of 140 Hz or higher.

FIG. 11 shows results of evaluations when varying the amplitude of thedrive signal. In the sensory evaluations, the frequency of the drivesignal to drive the drive unit 14 was 170 Hz, the period was 1 periodand the waveform was the sine wave. The signal amplitude was varied suchthat, in a state with no load in which the touch panel 12 was notpressed, the touch panel 12 is vibrated with predetermined amplitude ina range of 1-35 μm. Under a condition of the vibration amplitude with noload, the drive unit 14 was driven when a load of 1.5 N was applied tothe touch panel 12 in order to evaluate according to each item. Ahorizontal axis in FIG. 11 represents the vibration amplitude when theload of 1.5 N was applied corresponding to that with no load. As aresult, as can be seen in FIG. 11, it was confirmed that, in a statewith the load of 1.5 N, the human can sufficiently obtain the clicksensation if the vibration amplitude is 15 μm or more. That is, thehuman can obtain the click sensation by, in a state with the load of 1.5N on the touch panel 12, a vibration of the touch panel 12 only 1 periodat the constant frequency of 170 Hz with the vibration amplitude of 15μm or more.

FIG. 12 shows results of evaluations when varying the period(wavelength), that is, drive time. In the sensory evaluations, thewaveform of the drive signal to drive the vibration unit 14 was the sinewave, the signal amplitude was set to a level which causes the vibrationamplitude of 15 μm in a state of the predetermined standard load beingapplied on the touch panel 12, the frequency was 170 Hz and the periodwas varied in a range of 1/4 to 3 periods. For 1/4 period and 1/2period, the signal amplitude was set such that a vibration displacementon the touch panel 12 was approximately the same as those in otherperiods, that is, to a level at which the vibration amplitude ofapproximately 15 μm is obtained. As a result, as can be seen in FIG. 12,the highest evaluation was obtained when the period (wavelength) was 1period. In addition, it was also confirmed that, although basically goodresults were obtained in 5/4 periods and less than 1 period, it differedfrom the click sensation of the mobile terminal in 3/2 or more periods.

FIG. 13 shows results of evaluations when varying the waveform of thedrive signal. In the sensory evaluations, a sine wave, a square wave anda triangle wave were used as the waveform of the drive signal to drivethe vibration unit 14. In addition, the frequency of each signal is 170Hz, the signal amplitude was set to a level which causes the vibrationamplitude of 15 μm in the state of the predetermined standard load beingapplied to the touch panel 12, and the period was 1 period. As a result,as can be seen in FIG. 13, the highest evaluation was obtained by thesine wave.

Here, the drive signal of the sine wave (input voltage of the drive unit14), as shown by a dashed line in FIG. 14, may be the voltage in 1period from any phase not only 1 period in which the voltage increasesfrom 0 degree phase and then decreases but also, such as, 1 period inwhich the voltage decreases from 180 degree phase and then increases.FIG. 14 also shows a waveform (broken line) of the vibration amplitudeof the touch panel 12 under no load and a waveform (solid line) of thevibration amplitude of the touch panel 12 under a load of 1.5 N when thedrive unit 14 is driven by the input voltage shown by the dashed line.

From the exemplary results of the evaluations described above, it wasconfirmed that, when the input apparatus designed as shown in FIG. 5 andFIG. 6 is applied to a mobile terminal, it is possible to provide theoperator with the realistic click sensation by, at a point when a loadsatisfying the predetermined standard is applied to the touch panel 12in pressing, vibrating the touch panel 12 by approximately 15 μm or morewith the drive signal of 5/4 period or less, preferably 1 period of thesine wave with the constant frequency of 140 Hz or more, preferably 170Hz, for example. It was also confirmed that the same results can beobtained by the input apparatus designed as shown in FIG. 8 and FIG. 9.

Third Embodiment

When the human operates the push-button switch, the human is given atactile stimulus at a finger by the push-button switch not only inpressing but also in releasing, as shown in FIG. 4. As such, an inputapparatus according to a third embodiment of the present invention,using the input apparatus according to the first and the secondembodiments, provides the operator with the click sensation in releasingas well (hereinafter, the click sensation in releasing is referred to asthe release tactile sensation, arbitrarily). Thereby, it provides theoperator with a more realistic click sensation. The following is adescription of operations by the input apparatus according to thepresent embodiment, using the constitution shown in FIG. 5 and FIG. 6 asan example.

FIG. 15 shows a flowchart of operations by the input apparatus accordingto the present embodiment. As described with reference to FIG. 7, first,the control unit 15 detects that the input to the touch panel 12 is theinput to the input object displayed on the display panel 11, and thatthe pressure load detected by the load detection unit 13 increases bypressure on the touch panel 12 and reaches a predetermined standard forreceiving the input (step S81). Then, the control unit 15 receives theinput to the touch panel 12 at a point of such detection, as well asdriving the vibration unit 14 with a predetermined drive signal tovibrate the touch panel 12 in a predetermined vibration pattern (stepS82).

Then, when detecting that the load detected by the load detection unit13 satisfies the predetermined standard (step S83), the control unit 15drives the vibration unit 14 with the predetermined drive signal in thesame manner as in pressing, in order to vibrate the touch panel 12 in apredetermined vibration pattern (step S84).

Here, the predetermined standard load in releasing at step S83, that is,detected after a pressure input is received, may be set to any loadequal to or less than the predetermined standard load in pressingdetected at the step S81. In addition, the drive signal to drive thevibration unit 14 in releasing at step S84 may be either the same as ordifferent from that in pressing at step S82. For example, the frequencyof the drive signal in pressing at which an input to the touch panel 12is received may be set to 170 Hz, and the frequency of drive signal inreleasing may be set to 125 Hz as shown in FIG. 4, for example.

As stated above, it is possible to provide the release tactile sensationby, when the predetermined standard load is satisfied in releasing afterthe pressure input is received, driving the vibration unit 14 with thepredetermined drive signal and vibrating the touch panel 12 in thepredetermined vibration pattern in the same manner as that in pressing.Accordingly, in combination with the click sensation in pressing, it ispossible to provide the operator with the click sensation more similarto that of the push-button switch.

For example, in a case where the standard load of pressing to drive thevibration unit 14 and that of releasing are set to be equal, it ispossible to provide the click sensation in pressing and in releasing asshown in FIG. 16 if a maximum load in pressing exceeds the standardload. Accordingly, it is possible to provide the operator with the clicksensation more similar to that of the push-button switch. It is to benoted that, in FIG. 16 and other figures, “Cli” and “Ck” represent theclick sensation the human feels.

In a case where the standard load of releasing to drive the vibrationunit 14 is set any load lower than that of pressing, even if the maximumload in pressing is the standard load of pressing, that is, even if anpressing object is pulled back at the standard load of pressing, it ispossible to provide the click sensation in pressing and in releasing, asshown in FIG. 17. As shown in FIG. 16, in a case where the standard loadof pressing to drive the vibration unit 14 and that of releasing are setto be equal, if the maximum load in pressing is equal to the standardload, the vibration unit 14 may not be driven in releasing. In addition,if the operator tried to maintain the pressure load at the standardload, an unexpected release tactile sensation may be provided. As aresult, it may give the operator the feeling of strangeness. Incontrast, if the standard load of releasing to drive the vibration unit14 is set to any load lower than that of pressing, as shown in FIG. 17,it ensures to provide the release tactile sensation in releasing.Accordingly, it is possible to ensure that the operator is provided withthe click sensation more similar to that of the push-button switch.

The following is a description of the results of sensory evaluations ofthe click sensation of the input apparatus according to the thirdembodiment examined by the inventors when the vibration unit 14 wasdriven only in pressing and when driven both in pressing and inreleasing.

FIG. 18 is a diagram illustrating exemplary results of such evaluations.In FIG. 18, bars on the left side represent results of the evaluationswhen the vibration unit 14 was driven only in pressing, that is,“without the release tactile sensation”, whereas bars on the right siderepresent results of the evaluations when the vibration unit 14 wasdriven both in pressing and in releasing, that is, “with the releasetactile sensation”. The subjects were the five people involved in thesensory evaluations shown in FIG. 2 and FIG. 3. Evaluation items werefour items including “good feedback (easy to percept)” in addition tothe three evaluation items in FIG. 10 to FIG. 13. Each item is on ascale of 1 to 7 and the score of each item represents an average scoreof the five people. For the item “good feedback”, “bad” scores 1 and“good” scores 7. In addition, the same predetermined standard load todrive the vibration unit 14 and the same drive signal are used inpressing and releasing. Here, the predetermined standard load was 1.5 N.In addition, the drive signal was 1 period of the sine wave with thefrequency of 170 Hz and vibrated the touch panel 12, under the pressureof 1.5 N, by approximately 15 μm.

As can be seen in the results of the evaluations in FIG. 18, it wasconfirmed that, if the release tactile sensation is provided byvibrating the touch panel 12 in releasing as well, the click sensationbecomes more similar to that of the mobile terminal and a good feedback(perception) can be obtained.

Fourth Embodiment

Incidentally, the input apparatus used in a mobile terminal, forexample, is often used for a so-called repetitive tap to continuouslyinput the same input object in inputting a phone number, a message andthe like. In such a case, if the touch panel 12 is vibrated in thepredetermined vibration pattern not only in pressing but also inreleasing as shown in FIG. 18, it is necessary to appropriately set thepredetermined standard load of releasing to drive the vibration unit 14.

That is, when the human quickly performs the continuous input, a nextinput is generally started before the pressure load returns to “0” andthe maximum load in pressing varies. In such a case, if thepredetermined standard load of pressing and that of releasing to drivethe vibration unit 14 are set to be equal as described in the thirdembodiment, it may cause a phenomenon as shown in FIG. 19. That is, ifthe pressure load is pulled back at the standard load during therepetitive tap, for this input the vibration unit 14 may not be drivenin releasing or the click sensation may be provided before the operatorrecognizes to have released. As a result, the input operation and theclick sensation do not synchronize possibly giving the operator thefeeling of strangeness. FIG. 19 shows a case where a pressure load on athird input in four continuous input is pulled back from the standardload.

On the other hand, if the predetermined standard load of releasing todrive the vibration unit 14 is set too low in comparison with a load todrive the vibration unit 14 in pressing, a phenomenon as shown in FIG.20 may be caused. That is, if a next input is performed before the loadreturns to the standard load of releasing during the repetitive tap, thesensation is not provided in synchronization. As a result, it may givethe operator the feeling of strangeness. FIG. 20 shows a case where athird input in a four repetitive taps is performed before a load ofreleasing a second input reaches the standard load of releasing. Inaddition, if the predetermined standard load of releasing is too low asstated above, it takes time to return thereto. As a result, the operatordoes not feel the feeling of strangeness by the tactile sensationprovided but it takes time to allow a next input and thus prevents theoperator from operating quick continuous input even if the operatordesires it. Thereby, there is a concern that it may deteriorateoperability at the continuous input (repetitive tap).

In contrast, if the predetermined standard load of releasing to drivethe vibration unit 14 is set close to the load to drive the vibrationunit 14 in pressing, it enables quicker continuous input. However, ifthe operator tries to maintain a pressed state (hold) during thecontinuous input, an unexpected release tactile sensation may beprovided to the operator giving the feel of strangeness. That is, whenthe pressed state is held during the continuous input, the load slightlyvaries even though the operator intends to maintain the pressure loadconstant. Therefore, as shown in FIG. 21, for example, if a load rangebetween the standard load of pressing and that of releasing is smallerthan a load variation range in a holding state as described above, theoperator is provided with the release tactile sensation despite thinkingoneself holding and thus has the feeling of strangeness.

As such, according to the fourth embodiment of the present invention, itenables to deal with the above operability problem at the continuousinput and slight variations in the load in the holding state, allowingthe operator to perform continuous input smoothly with feeling therealistic click sensation. Therefore, the input apparatus according tothe fourth embodiment, using the input apparatus in the thirdembodiment, sets the predetermined standard load of releasing to drivethe vibration unit 14 at a value in a range of 50-80% of that ofpressing.

The following is a description of results of sensory evaluations of theclick sensation of the input apparatus according to the fourthembodiment examined by the inventors.

FIG. 22 to FIG. 24 are diagrams illustrating the results of theseevaluations. In FIG. 22 to FIG. 24, the subjects were the five peopleinvolved in the sensory evaluations shown in FIG. 18. Evaluation itemswere five items including “easy for repetitive tap” in addition to thefour items in FIG. 18. Each item is on a scale of 1 to 7 and the scoreof each item represents an average score of the five people. For theitem “easy for repetitive tap”, “No” scores 1 and “Yes” scores 7. Inaddition, both in pressing and in releasing, the drive signal to drivethe vibration unit 14 was 1 period of the sine wave with the frequencyof 170 Hz, and vibrated the touch panel 12 by approximately 15 μm wheneach predetermined standard was satisfied.

FIG. 22 shows results of evaluations when the predetermined standardload in pressing was 1 N and the predetermined standard load ofreleasing was 0 N, 0.5 N and 1 N. As can be seen in FIG. 22, if thepredetermined standard load to start vibration in pressing was 1 N, thehighest evaluations for all items were obtained when the predeterminedstandard load to start vibration in releasing was 0.5 N.

FIG. 23 shows results of evaluations when the predetermined standardload in pressing was 2 N and the predetermined standard load inreleasing was 0 N, 0.5 N, 1 N, 1.5 N and 2 N. As can be seen in FIG. 23,if the predetermined standard load to start vibration in pressing was 2N, high evaluations were obtained when the predetermined standard loadto start vibration in releasing was 1 N and 1.5 N. The highestevaluations for all items were obtained especially with 1.5 N.

FIG. 24 shows results of evaluations when the predetermined standardload in pressing was 3 N and the predetermined standard load inreleasing was 0 N, 0.5 N, 1 N, 1.5 N, 2 N, 2.5 N and 3 N. As can be seenin FIG. 24, if the predetermined standard load to start vibration inpressing was 3 N, high evaluations were obtained when the predeterminedstandard load to start vibration in releasing was 1.5 N, 2 N and 2.5 N.The highest evaluations for all items were obtained especially with 2 N.

From the exemplary results of the evaluations described above, it wasconfirmed that, by setting the predetermined standard load of releasingto drive the vibration unit 14 to a value in the range of 50-80% of thatof pressing, the realistic click sensation is provided by synchronizinga sequential input and timing to provide the feeling during thecontinuous input (repetitive tap) without giving the feeling ofstrangeness. That is, the predetermined standard load of releasing isset to be smaller than but equal to or over 50% of that of pressing.Thereby, the operability at the continuous input is dramaticallyimproved without giving the feeling of strangeness. In addition, thepredetermined standard load of releasing is set to be equal to or under80% of that of pressing. Thereby, it is possible to deal with slightvariations in the holding state during the continuous input.

Accordingly, if the predetermined standard load of pressing is set 1 N,for example, that of releasing is set at any value from 0.5 N to 0.8 N.In addition, if the predetermined standard load of pressing is high, theload variation range in the holding state is wider than that when thepredetermined standard load is low. In such a case also, thepredetermined standard load of releasing is set in the range of 50-80%of that of pressing. For example, if the predetermined standard load ofpressing is set high, 6 N, the predetermined standard load in releasingis set to 3 N-4.8 N. Thereby, it is possible to provide the realisticclick sensation in synchronization with the continuous input withoutproviding unexpected release tactile sensation and giving the feeling ofstrangeness. The predetermined standard load of pressing and that ofreleasing may be set either fixedly or selectively arbitrarily by theuser.

It is to be understood that the present invention is not limited to theembodiments set forth above and various modifications and changes may beimplemented. For example, the load detection unit may be constituted ofany number of strain gauge sensors. In addition, the load detection unitmay be constituted according to an input detection scheme of the touchpanel. For example, the load detection unit can be constituted withoutusing the strain gauge sensor if the load can be detected from a changeof an output signal based on a resistance change in accordance with acontact area in a case of employing the resistive film scheme or on achange in capacitance in a case of employing the capacitive scheme. Inaddition, the vibration unit may be constituted of any number ofpiezoelectric vibrators, transparent piezoelectric elements provided onan entire operation surface of the touch panel, or an eccentric motorwhich rotates 360 degrees in 1 period of the drive signal.

In addition, if the input apparatus has the display panel as shown inFIG. 5 and FIG. 6, the control unit may control so as to change adisplay state of a corresponding input object on the display panel byinversion or the like, upon receiving an input to the touch panel.Moreover, the control unit may be configured to change the drive signalto drive the vibration unit based on an input position detected on thetouch panel so as to change the click sensation.

The present invention is applicable to an input apparatus with an inputunit serving as one switch. Also, the input apparatus according to thepresent invention is capable of providing feelings of a multistepswitch, such as a two-step switch (pressed further after pressed), bysequentially providing the click sensations on different standards(loads) while the input unit is being pressed. Thereby, if the inputapparatus is applied to a release button of a camera, for example, it ispossible to provide a feeling to lock focus (first step) and a feelingto release (second step). In addition, in combination with the displayunit, it is possible to change a display of a menu screen and the likein a variety of manners in accordance with the step. Moreover, whenproviding the feelings of the multistep switch, it is possible to changethe drive signal to vibrate the input unit by the vibration unit at eachstep in order to provide a different click sensation at each step.

According to the present invention, the vibration unit is driven whenthe pressure load detected by the load detection unit satisfies apredetermined standard for receiving an input. Here, “when the pressureload detected by the load detection unit satisfies the predeterminedstandard for receiving an input” may represent “when the pressure loaddetected by the load detection unit reaches the predetermined value forreceiving the input”, “when the pressure load detected by the loaddetection unit exceeds the predetermined value for receiving the input”,or “when a predetermined value for receiving an input is detected by theload detection unit”.

The control unit vibrates the input unit (touch panel) in apredetermined vibration pattern by driving the drive unit when thepressure load detected by the load detection unit satisfies thepredetermined standard, and such predetermined vibration pattern inpressing may be one as shown by the solid line in FIG. 4, whereas thatin releasing may be another as shown by the dashed line in FIG. 4.Vibration of the input unit in those manners enables to provide theoperator with the click sensation (vibration stimulus) the same as thatobtained when operating the push-button switch.

REFERENCE SIGNS LIST

-   11 display panel-   12 touch panel-   13 load detection unit-   14 vibration unit-   15 control unit-   21 housing-   22 insulator-   23 upper cover-   24 insulator-   31 strain gauge sensor-   32 ultrasonic transducer-   41 touch panel-   41 a input object-   42 position detection unit-   43 display panel-   44 load detection unit-   45 vibration unit-   46 control unit

1. An input apparatus comprising: an input unit for receiving a pressureinput; a load detection unit for detecting a pressure load on the inputunit; a vibration unit for vibrating the input unit; and a control unitfor driving the vibration unit with a single drive signal when thepressure load detected by the load detection unit satisfies apredetermined standard for receiving an input to the input unit, whereinthe drive signal has a frequency of 140 Hz or higher, and the drivesignal is used for a period determined in a range from 1/4 period to 5/4period of the drive signal.
 2. A control method of an input apparatuscomprising an input unit for receiving a pressure input, a loaddetection unit for detecting a pressure load on the input unit and avibration unit for vibrating the input unit, the control methodcomprising the step of: driving the vibration unit with a single drivesignal when the pressure load detected by the load detection unitsatisfies a predetermined standard for receiving an input to the inputunit, wherein the drive signal has a frequency of 140 Hz or higher, andthe drive signal is used for a period determined in a range from 1/4period to 5/4 period of the drive signal.